Dr Juffali, 60, claims he has made "generous" provision for his ex-wife, giving her a property in Beverly Hills, California, paying her 100,000 US dollars (£70,700) per month and meeting all the expenses of their 13-year-old daughter.

However Ms Estrada, 53, says Dr Juffali, 60, obtained their divorce without her knowledge and is demanding a financial settlement for their 13-year marriage.

Dr Juffali was appointed as the permanent representative for St Lucia to the London headquarters of the International Maritime Organisation (IMO) in April 2014.

The post grants Dr Juffali diplomatic immunity - exempting him from the UK laws - and may effectively grant him protection from having to settle Ms Estrada’s demands.

According to papers before the court now made public for the first time, Ms Estrada's claim, if successful, could potentially be worth "many millions of pounds".

Dr Juffali says he already pays Ms Estrada and intends to make further provision for her "at the appropriate time".

He is asking family judge Mr Justice Hayden to strike out his ex-wife's claim on the basis that he is protected from legal action in the UK by diplomatic immunity.

Lawyers for Ms Estrada are arguing in a four-day court hearing that his immunity is limited to his official, diplomatic functions and does not extend to the family court proceedings because he is "a permanent resident" of the UK with strong and enduring ties to the country, including those with his ex-wife and his daughter, who was born in England.

Walid Juffali with his former wife Christina Estrada at the Cannes Film Festival in 2001 Photo: Alan Davidson

They also say he acquired from his mother Bishopsgate House, a 10-bedroom property set in 40 acres adjoining Windsor Great Park which was the matrimonial home and valued in the region of £100 million.

They state in written submissions before the court that he also acquired a £41 million property in Walton Place, Kensington and Chelsea, south-west London, and a substantial property in Devon.

It is argued that, although the properties are now subject to trust and corporate structures, they are clear indications of his very close ties to England.

Disagreeing, Dr Juffali's legal team say the former husband has substantial property elsewhere, including in Jeddah, Saudi Arabia, and does not permanently reside in the UK.

Thus, they submit, he enjoys "general immunity" from being sued in the UK courts, including by his ex-wife, under Article 15 of the International Maritime Organisation (Immunities and Privileges) Order 2015.

The government has issued a statement saying: "The government of Saint Lucia has been assured by the FCO that Dr Juffali has not abused the privileges and immunities afforded to him, nor is the decision of the government of Saint Lucia to uphold the principle of diplomatic immunity an abuse of these privileges or immunities in any way.

"While the government of Saint Lucia fully respects the decision of the FCO to make such a request, it is not satisfied, based on its own examination of the facts, that a compelling case has been made out to grant a waiver of the diplomatic immunity of Dr Juffali."

The statement added that Saint Lucia had maintained its position "that the parties should be allowed to settle their matrimonial dispute through negotiations and failing that, the courts should decide if immunity can be waived in this matter.”